Traffic can only start after the Chinese contractor has completed the necessary software fixes and safety tests conclude satisfactorily, he said.

A train control system, critical for the start of passenger traffic, not yet used in Europe but long used in China, has been installed, but software problems have been found, and the errors need to be corrected, he added.

If the repairs are carried out in the coming days and weeks as promised, the first “dark-run tests” could start in the first half of August. If these are successful, passenger trains could start operating as early as September, Vitézy said.